Welcome back to the fold (in advance)
Coming from a Non PE to a PE - there doesn't feel a lot in it performance wise- from a personal perspective, I just wanted the "latest" model having had my previous 6 for 2 years - I also liked the PE wheels more too.
Economy wise, if you drive it sensibly, 35mpg is possible on a run. In town it's around 17mpg and if you're playing with it, single figures. I get around real range 350miles to a tank and £78 to fill it with momentum
As for colours - Riviera is beautiful. Nardos are popular (I went for one) - I'd steer clear of Misano and White (just personal choice and they seem to hang around on forecourts longer) - Nardo being a flat colour is also easy to paint - Mines done 21k and is starting to look a little chippy at the front. As with my previous sepang blue, the base colour is white, so chips can be quite noticeable.
Personally, I love the alcantara interior over the full leather - looks way nicer though the caveat is that your arse doesn't move an inch when you are in them, you can't slide around on the seat. Plus it marks easily.
Spec wise, this has been done to death on numerous threads.....but for me, Pan Roof was a deal breaker as was HUD. As time goes by and come resale, values will all fall into line, therefore when you have your hard earned cash, from a selling perspective, the car with the better spec will be the one that goes first (assuming all other parameters are in line, servicing records etc etc) - wouldn't bother with the OEM sports exhaust as a must have as it's not that noisy and an aftermarket, Milltek will transform the noise, though p1ss the neighbours off
The Golf R, Audi S1 and Audi S3 boys will make your life hell too asking you to blip the throttle. M3 and M4 drivers will be having a go, to prove that their rep mobile with 20's can keep up - (they can't)
Interestingly enough, my PE doesn't have the DRC, whereas my previous 6 did - as a number of other owners myself included, a % of cars have had their DRC fail, I think it's around £1500 a corner if its not in warranty. I've not really noticed the difference on my current car - the DRC has increased speed limit too, though mine, not having DRC is supposed to be limited to 155mph - (it's not

)
I'd steer clear of modded ones that are under 3 years old, purely from the TD1 code it will throw up and the hassle Audi Stealers will give you if something such as DRC were to fail, despite them having to theoretically demonstrate that a Map was instrumental in causing a failure of X or Y parts.
Shout if you have anymore questions. Either way, whichever model you go for you'll love it.....
When you come to buy, ask when the discs and pads were replaced - they tend to last around 20-23k miles and are around £1200 for a front set and £800 for rears. Tyres last circa (mine) around 15k and mine has an easy life. £220 / corner - Costco.